Two-way video systems are available that include a display and camera in each of two locations connected by a communication channel that allows communication of video images and audio between two different sites. Originally, such systems relied on setup at each site of a video monitor to display a remote scene and a separate video camera, located on or near the edge of the video monitor, to capture a local scene, along with microphones to capture the audio and speakers to present the audio thereby providing a two-way video and audio telecommunication system between two locations. Such systems are typically large, fixed in location, have a restricted ability to cope with changes in scene focus, and do not necessarily provide natural communication. Moreover, these designs do not take advantage of available, portable display and capture systems such as are found in cellular telephones.
Referring to FIG. 5, a typical prior art two-way telecommunication system is shown wherein a first user 20a views a first display 14a. A first image capture device 10a, which can be a digital camera, captures an image of the first viewer 20a. If the image is a still digital image, it can be stored in a first still image memory 30a for retrieval. A still image retrieved from first still image memory 30a or video images captured directly from the first image capture device 10a will then be converted from digital signals to analog signals using a first D/A converter 40a. A first modulator/demodulator 50a then transmits the analog signals using a first communication channel 60 to a second display 14b where a second user 20b can view the captured image(s) on a display 14b. 
Similarly, second image capture device 10b, which can be a digital camera, captures an image of second viewer 20b. The captured image data is sent to a second D/A converter 40b to be converted to analog signals but can be first stored in a second still image memory 30b for retrieval. The analog signals of the captured image(s) are sent to a second modulator/demodulator 50b and transmitted through a second communication channel 62 to the first display 14a for viewing by first viewer 20a. The first communication channel 60 may be the same as the second communication channel 60.
Although such systems have been produced and used for teleconferencing and other two-way communications applications, there are some significant practical drawbacks that have limited their effectiveness and widespread acceptance. Expanding the usability and quality of such systems has been the focus of much recent research, with a number of proposed solutions directed to more closely mimicking real-life interaction and thereby creating a form of interactive virtual reality. A number of these improvements have focused on communication bandwidth, user interface control, and the intelligence of the image capture and display components of such a system. Other improvements seek to integrate the capture device and display to improve the virtual reality environment.
There have been a number of solutions proposed for addressing the problem of poor eye contact that is characteristic of many existing solutions. With conventional systems that follow the pattern of FIG. 1, poor eye contact results from locating the video camera on a different optical axis than the video monitor and causes the eyes of an observed participant to appear averted, which is undesirable for a video communication system. Traditional solutions for addressing this problem, employing a display, camera, beam splitter, and screen, are described in a number of patents, including U.S. Pat. No. 4,928,301 entitled “Teleconferencing terminal with camera behind display screen” to Smoot; U.S. Pat. No. 5,639,151 entitled “Pass-through reflective projection display” and U.S. Pat. No. 5,777,665 entitled “Image blocking teleconferencing eye contact terminal” to McNelley, et al.; and U.S. Pat. No. 5,194,955 entitled “Video telephone” to Yoneta et al., for example. Alternately, commonly assigned U.S. Patent Application Publication No. 2005/0024489 entitled, “Image capture and display device” by Fredlund et al. describes a display device for capturing and displaying images along a common optical axis. However, all of these solutions are relatively expensive and may be difficult to implement in a portable format.
One difficulty with a number of conventional solutions relates to an inability to compensate for observer motion and changes in the field of view. Among approaches to this problem have been relatively complex systems for generating composite simulated images, such as that described in U.S. Patent Application Publication No. 2004/0196360 entitled “Method and apparatus maintaining eye contact in video delivery systems using view morphing” by Hillis et al. Another approach to this problem is proposed in U.S. Pat. No. 6,771,303 entitled “Video-teleconferencing system with eye-gaze correction” to Zhang et al. that performs image synthesis using head tracking and multiple cameras for each teleconference participant. These solutions are complex and may not be suitable for portable imaging and display devices or systems in which the location and orientation of the observers can vary greatly with respect to the location and orientation of the display or camera.
Video-conferencing systems incorporating sophisticated image analysis for improving usability and presence are known in the prior art. For example, EP1536645A1 entitled “Video conferencing system with physical cues” describes a system having robotic units that represents a remote conference participant. However, such systems are extremely complex and may not be suitable for small, portable systems. Face recognition algorithms that can identify and extract human faces in an image are also known, for example as described in U.S. Patent Application Publication No. 2005/0047647. Such techniques may be applied to image processing tasks, for example red-eye removal as described in WO2006045441 entitled “Method and Apparatus for Red-Eye Detection in an Acquired Digital Image.”
The proliferation of solutions proposed for improved teleconferencing and other two-way video communication shows how complex the problem is and indicates that significant problems remain.